Search:
Submit Search


HW audio levels

Please note: we can't provide official support for the Free Edition, but other users might be able to help you here.

HW audio levels

Postby mumblecake » Tue Jun 02, 2015 4:41 am

Hi,

There has been a very interesting post about audio levels on Contrebombarde:

Contrebombarde article

One of the recommendations in case of distorted sound was to check the audio levels and to make sure that if you are using consumer grade hardware that the HW audio level is set to -10dB while for pro-grade it can be up to +4dB.

This was based on the wikipedia article for audio levels:

http://en.wikipedia.org/wiki/Line_level

As can be seen there ARE different levels for consumer grade and pro-grade hardware but a closer look emphasizes that it is not just a difference of +14dB. Instead both standards are actually using different units (consumer grade = dBV (decible Volt), pro-grade dBu (decible unloaded ... in contrast to the archaich telephone standard which was loaded with a 600Ohm impedance)).

Looking at:

http://en.wikipedia.org/wiki/Decibel#Voltage

it is clear that while both units are connected they are not the same and in particular that the difference in sound-level from -10dBV to +4dBu is not 14dB.

Now the important question is: How does HW link into these two standards. In particular how does the unit-less audio level in Hauptwerk relate to the physical units of dBV and dBu.

Going even further: what would the recommended settings be for consumer grade and for pro-grade hardware?

Thanks you very much

Best regards

Mathis
mumblecake
Member
 
Posts: 104
Joined: Mon Feb 23, 2015 11:03 am

Re: HW audio levels

Postby mdyde » Tue Jun 02, 2015 5:32 am

Hello Mathis,

An 'Audio trim dB' setting of 0 dB in Hauptwerk simply means that Hauptwerk will send its digital audio output stream to your audio interface's driver at the amplitude at which the sample set creator specified as the default. Any other value decreases or increases the level of that digital signal relative to that point, in decibels.

Hence if you set the 'Audio trim dB' setting to -6 dB, for example, then Hauptwerk's digital output stream to your audio interface's driver would be at approximately half of the amplitude, compared to 0 dB.

Hauptwerk can have no knowledge of, or further influence over, what you audio interface and speakers do with that digital signal subsequently (in terms of analogue conversion, circuitry, impedance, dBu/dBV values, etc.). Those things are determined by your audio interface hardware and the settings within its driver's control panel.

This is our advice from the Hauptwerk user guide ('Performance tuning: Setting the audio output level' section, pages 212-213 in the current v4.2.0 version) on setting 'Audio trim dB':

The meter always shows the highest (peak) level of all audio channels.

If it goes into the red region then loud ‘crackles’ (severe audio distortion, 'clipping') are highly likely and you should use the Trim dB adjustments to reduce the level until the meter no longer goes into the red.

Having the output level set too low loses some audio quality/resolution, so it's best to adjust the trim setting so that the meter very occasionally just goes into the yellow when playing with the loudest registration you use, but never into the red.


Then adjust the signal level meters, and dBV/dBu setting, within your audio interface's control panel appropriately for your hardware.
Best regards,
Martin.

[Please use email or the Contact page if you need to contact us privately, rather than private forum messages.]

Image
User avatar
mdyde
Moderator
 
Posts: 10241
Joined: Fri Mar 14, 2003 2:19 pm
Location: UK

Re: HW audio levels

Postby mumblecake » Tue Jun 02, 2015 5:42 am

Hi Martin,

thank you for the clarification. I thought you might have had low level driver access to the physical output amplitude but then I guess that would require some extreme-indepth knowledge of the hardware in use ... which could clearly not been done to support a wide range of hardware.

Best regards

Mathis
mumblecake
Member
 
Posts: 104
Joined: Mon Feb 23, 2015 11:03 am

Re: HW audio levels

Postby mdyde » Tue Jun 02, 2015 5:54 am

Thanks, Mathis.

Only the audio interface's hardware driver has that level of knowledge/control. That's what drivers are for.
Best regards,
Martin.

[Please use email or the Contact page if you need to contact us privately, rather than private forum messages.]

Image
User avatar
mdyde
Moderator
 
Posts: 10241
Joined: Fri Mar 14, 2003 2:19 pm
Location: UK


Return to Free Edition support (users supporting users)

Who is online

Users browsing this forum: No registered users and 1 guest